refactor: rename project to LedGrab, split HA integration into separate repo

- Rename Python package: wled_controller -> ledgrab
- Rename env var prefix: WLED_ -> LEDGRAB_ (with auto-migration for old vars)
- Rename localStorage key: wled_api_key -> ledgrab_api_key (with migration)
- Rename HA integration domain: wled_screen_controller -> ledgrab
- Update all imports, build scripts, Docker, installer, config, docs
- Remove HA integration (moved to ledgrab-haos-integration repo)
- Remove hacs.json (belongs in HA repo now)
- Add startup warning for users with old WLED_ env vars
- All tests pass (715/715), ruff clean, tsc clean, frontend builds

server/esbuild.mjs

@@ -1,6 +1,6 @@
 import * as esbuild from 'esbuild';
 
-const srcDir = 'src/wled_controller/static';
+const srcDir = 'src/ledgrab/static';
 const outDir = `${srcDir}/dist`;
 
 const watch = process.argv.includes('--watch');